function rslice_usage()
% RSLICE_USAGE:  Prints a general usage message

fprintf ( 1, 'RSLICE Usage:\n' );
fprintf ( 1, '    RSLICE(''PropertyName'',PropertyValue,...)\n' );
fprintf ( 1, '                                              \n' );
fprintf ( 1, '    where the ''PropertyName'' and ''PropertyValue'' pairs can be given as\n' );
fprintf ( 1, '    follows.                                                              \n' );
fprintf ( 1, '                                                                           \n' );
fprintf ( 1, '   ''directory'':                                                          \n' );
fprintf ( 1, '        The ROMS input is a set of files in the given directory.  This     \n' );
fprintf ( 1, '        property must be accompanied by ''regexp'' (see below).            \n' );
fprintf ( 1, '   ''file'':                                                               \n' );
fprintf ( 1, '        The PropertyValue is the path to a single local netCDF file.  This \n' );
fprintf ( 1, '        is usually the only PropertyName/PropertyValue pair you need to    \n' );
fprintf ( 1, '        provide.                                                           \n' );
fprintf ( 1, '   ''regexp'':                                                             \n' );
fprintf ( 1, '        A regular expression that describes the set of netCDF files to be  \n' );
fprintf ( 1, '        used as input.  Used in conjunction with ''directory''.  This      \n' );
fprintf ( 1, '        allows rslice to use just a subset of all the netCDF files that    \n' );
fprintf ( 1, '        may reside in the given directory.  See also REGEXP.               \n' );
fprintf ( 1, '   ''spatial'':                                                            \n' );
fprintf ( 1, '        If given as 1, then non-temporal variables, such as ''lon_rho''    \n' );
fprintf ( 1, '        for example, will be loaded as well.  Default is 0.  If given, the \n' );
fprintf ( 1, '        PropertyValue must be numeric.                                     \n' );
fprintf ( 1, '   ''time_dimension'':                                                     \n' );
fprintf ( 1, '        The PropertyValue is the name of the dimension upon which the time \n' );
fprintf ( 1, '        variable is defined.  The default is ''ocean_time''.               \n' );
fprintf ( 1, '   ''time_variable'':                                                      \n' );
fprintf ( 1, '        The PropertyValue is the name of the time variable.  The default is\n' );
fprintf ( 1, '        ''ocean_time''.                                                    \n' );
fprintf ( 1, '   ''url'':                                                                \n' );
fprintf ( 1, '        The Roms input is an OPeNDAP URL.  In order for this to work,      \n' );
fprintf ( 1, '        SNCTOOLS must be configured for OPeNDAP access.                    \n' );
fprintf ( 1, '   ''variable'':                                                           \n' );
fprintf ( 1, '        Specifies a default variable to be displayed when rslice first     \n' );
fprintf ( 1, '        starts.                                                            \n' );
fprintf ( 1, '   ''varlist'':                                                            \n' );
fprintf ( 1, '        Specifies a subset of variables that rslice will use.  All others  \n' );
fprintf ( 1, '        will be ignored.  The PropertyValue here must be a cell array.     \n' );
fprintf ( 1, '   ''verbose'':                                                            \n' );
fprintf ( 1, '        If given as 1, then a lot of debugging information will be printed.\n' );
fprintf ( 1, '        The default is 0.  This PropertyValue must be numeric.             \n' );
fprintf ( 1, '   ''vslice'':                                                             \n' );
fprintf ( 1, '        The PropertyValue is an Nx2 array of surface coordinates to use as \n' );
fprintf ( 1, '        a set of control points that defines a vertical slice line.        \n' );
fprintf ( 1, '   ''vslice_vel'':                                                         \n' );
fprintf ( 1, '        The PropertyValue is an Nx2 array of surface coordinates to use as \n' );
fprintf ( 1, '        a set of control points that defines a vertical slice line of      \n' );
fprintf ( 1, '        velocity.                                                          \n' );


